Scrimgeour Angus G, Stahl Chad H, McClung James P, Marchitelli Louis J, Young Andrew J
Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA.
J Nutr Biochem. 2007 Dec;18(12):813-9. doi: 10.1016/j.jnutbio.2006.12.018. Epub 2007 May 2.
To guide development of novel nutritional strategies aimed at reducing the incidence of stress fractures, we observed the effects of manipulating dietary zinc (Zn) content on bone integrity in Sprague-Dawley rats fed either a severely Zn-deficient (ZnD; 1 ppm), a moderately Zn-deficient (MZnD; 5 ppm) or a Zn-adequate (ZnAD; 30 ppm) diet for 6 weeks. At the completion of the diet period, body composition, bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) were determined in vivo by using dual-energy X-ray absorptiometry. Following euthanasia, long bones were collected for determination of Zn content and biomechanical strength testing. Despite significant positive correlations between dietary Zn and both body weight (BW) and bone Zn content for the entire cohort (r = .77 and r = .83, respectively), rats fed MZnD or ZnAD diets did not differ in feed intakes, body composition, BMC, BA, BMD or BW. Tibial bones, but not femur bones, appear to be more responsive to dietary Zn manipulation, as all bone biomechanical strength indices in the ZnAD-fed rats were significantly greater than in rats fed the ZnD diets. Rats fed either MZnD or ZnAD diets had stronger tibiae (129% increase in maximum load and stress at maximum load, P<.01) compared with those fed ZnD diets. The load at breakage for the tibial bones of rats fed MZnD diets was not different from the ZnD rats, but lower (P<.05) than that of the ZnAD rats. These results suggest that since feed intakes, body composition, BMC, BA, BMD and BW were not significantly different between the MZnD- and ZnAD-fed animals, the reduced bone integrity observed in the MZnD-fed rats resulted from dietary Zn inadequacy, and not as a result of the reduced growth that is typically associated with Zn deficiency.
为指导开发旨在降低应力性骨折发生率的新型营养策略，我们观察了在6周内给予斯普拉格-道利大鼠严重缺锌（ZnD；1 ppm）、中度缺锌（MZnD；5 ppm）或锌充足（ZnAD；30 ppm）饮食时，控制饮食锌（Zn）含量对骨完整性的影响。在饮食期结束时，使用双能X射线吸收法在体内测定身体成分、骨矿物质含量（BMC）、骨面积（BA）和骨矿物质密度（BMD）。安乐死后，收集长骨以测定锌含量并进行生物力学强度测试。尽管整个队列中饮食锌与体重（BW）和骨锌含量之间存在显著正相关（分别为r = 0.77和r = 0.83），但喂食MZnD或ZnAD饮食的大鼠在采食量、身体成分、BMC、BA、BMD或BW方面并无差异。胫骨似乎比股骨对饮食锌操纵更敏感，因为喂食ZnAD饮食的大鼠的所有骨生物力学强度指标均显著高于喂食ZnD饮食的大鼠。与喂食ZnD饮食的大鼠相比，喂食MZnD或ZnAD饮食的大鼠胫骨更强壮（最大负荷和最大负荷时的应力增加129%，P<0.01）。喂食MZnD饮食的大鼠胫骨的断裂负荷与ZnD大鼠无差异，但低于（P<0.05）ZnAD大鼠。这些结果表明，由于喂食MZnD和ZnAD饮食的动物在采食量、身体成分、BMC、BA、BMD和BW方面无显著差异，因此在喂食MZnD饮食的大鼠中观察到的骨完整性降低是由于饮食锌不足，而不是由于通常与锌缺乏相关的生长减少。
